core-lightning/contrib/pyln-client/README.md
Christian Decker 3418e59d76 pyln: Split pylightning into multiple pyln modules
This is the first step to transition to a better organized python module
structure. Sadly we can't reuse the `pylightning` module as a namespace module
since having importable things in the top level of the namespace is not
allowed in any of the namespace variants [1], hence we just switch over to the
`pyln` namespace. The code the was under `lightning` will now be reachable
under `pyln.client` and we add the `pyln.proto` module for all the things that
are independent of talking to lightningd and can be used for protocol testing.

[1] https://packaging.python.org/guides/packaging-namespace-packages/

Signed-off-by: Christian Decker <decker.christian@gmail.com>
2019-09-30 13:27:37 +02:00

2.6 KiB

pyln-client: A python client library for lightningd

This package implements the Unix socket based JSON-RPC protocol that lightningd exposes to the rest of the world. It can be used to call arbitrary functions on the RPC interface, and serves as a basis for plugins written in python.

Installation

pyln-client is available on pip:

pip install pyln-client

Alternatively you can also install the development version to get access to currently unreleased features by checking out the c-lightning source code and installing into your python3 environment:

git clone https://github.com/ElementsProject/lightning.git
cd lightning/contrib/pyln-client
python3 setup.py develop

This will add links to the library into your environment so changing the checked out source code will also result in the environment picking up these changes. Notice however that unreleased versions may change API without warning, so test thoroughly with the released version.

Examples

Using the JSON-RPC client

"""
Generate invoice on one daemon and pay it on the other
"""
from pyln.client import LightningRpc
import random

# Create two instances of the LightningRpc object using two different c-lightning daemons on your computer
l1 = LightningRpc("/tmp/lightning1/lightning-rpc")
l5 = LightningRpc("/tmp/lightning5/lightning-rpc")

info5 = l5.getinfo()
print(info5)

# Create invoice for test payment
invoice = l5.invoice(100, "lbl{}".format(random.random()), "testpayment")
print(invoice)

# Get route to l1
route = l1.getroute(info5['id'], 100, 1)
print(route)

# Pay invoice
print(l1.sendpay(route['route'], invoice['payment_hash']))

Writing a plugin

Plugins are programs that lightningd can be configured to execute alongside the main daemon. They allow advanced interactions with and customizations to the daemon.

#!/usr/bin/env python3
from pyln.client import Plugin

plugin = Plugin()

@plugin.method("hello")
def hello(plugin, name="world"):
    """This is the documentation string for the hello-function.

    It gets reported as the description when registering the function
    as a method with `lightningd`.

    """
    greeting = plugin.get_option('greeting')
    s = '{} {}'.format(greeting, name)
    plugin.log(s)
    return s


@plugin.init()
def init(options, configuration, plugin):
    plugin.log("Plugin helloworld.py initialized")


@plugin.subscribe("connect")
def on_connect(plugin, id, address):
    plugin.log("Received connect event for peer {}".format(id))


plugin.add_option('greeting', 'Hello', 'The greeting I should use.')
plugin.run()